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Gold is so soft and easily worked that you could roll an ounce of it into a hair-
thin wire 50 miles long.

DIFFERENT TYPES OF ROCKS
Rocks can be divided into three groups. They are igneous, sedimentary and
metamorphic rocks.

Granite Basalt Pumice
Igneous
Igneous RocksRocksRocks
Igneous
The word ‘igneous ’ means made from fire or heat . Igneous rocks are formed
from cooled magma. Sometimes, it cools on the surface to form rocks such as
basalt. Other magma is cooled underground to create rocks called granites.

Types of Igneous Rocks
Granite
It is a volcanic rock that is hardened under the ground. It is made up of quartz,

feldspar and several types of mica. Granite is found in red, pink, yellow or
brown colours. Granite is the most common igneous rock on the Earth’s

surface.
Basalt

Basalt rocks are formed when lava cools on the surface of the Earth. It is
dense and dark and has fine grains.

Pumice
Pumice is another light coloured rock formed by lava cooling quickly on the
Earth’s surface. It has a sponge-like structure because it is formed from foamy

lava. It is a stone that can float on water. Dentists use powdered pumice for
polishing teeth. It is also used as a scrubber to remove rough skin from the body.

Sedimentary RocksRocks
Sedimentary
Sedimentary Rocks
Rain, wind, rivers flowing down mountains, etc., wear down rocks on
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mountains. These small bits of rocks are then carried down and deposited
elsewhere. Repeated deposition presses down the lower layers and hardens
then into rock. Such rocks are called sedimentary rocks.

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